Extensible automobile aerials



Sept 2 1958 J. RcHAD'owsK; Erm. 2,850,305

EXTENSIBLE AUTOMOBILE AERIALS Filed Feb. 1,9, 1954 'n `INVENTORS JSEPH l? GHWSK/ BY /VTH/VY G. TUR/f A T TORNE YS v LA lllllllnl United States Patent O nxinNsruLn AUToMoBILE AERIALS loseph l. Chadowski, Shaker Heights, and Anthony G. Turk, Cleveland, Ohio, assignors to Cornell-Dubilier Electric Corporation, South Plainlield, N. J., a corporation of Delaware Application February 19, 1954, Serial No. 411,472

1 Claim. (Cl. 286-37) This invention relates generally to automobile aerials but has reference more particularly to the extensible or collapsible type of aerials.

A primary object of the invention is to provide an areial of the type described which is characterized by the use of a seal or sealing means which is eiective not only to prevent entry of water into the joints between the antenna mast and mast housing, but is also elective to prevent accumulation of moisture on the mast, thereby enabling the antenna to retain good electrical characteristics in wet weather.

Another object of the invention is to provide an antenna of the character described which is inexpensive, comprises a minimum number of parts, has excellent electrical and mechanical properties, and is highly pleasing in appearance.

A further object of the invention is to provide an antenna of the character described, having an end fittingv for the lead-in, the use of which eliminates the necessity for soldering and avoids flux corrosion and disturbance of 'the interlacing of the braid used in lead-ins, whereby a uniformly strong joint is obtained, as well as an eiiective water seal, without the use of extra parts.

Other objects and advantages of our invention will be apparent during the course of the following description.

in the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Fig. l is a View, partly in elevation and partly in section, of an antenna embodying the novel features of the invention;

Fig. 2 is a fragmentary cross-sectional view, on an enlarged scale, taken on the line 2 2 of Fig. l;

Fig. 3 is a-fragmentary elevational view, on an enlarged scale, of a portion of Fig. l;

Fig. 4 is a fragmentary cross-sectional view, on an enlarged scale, of a portion of Fig. 1, and

Fig. 5 is a view similar to Fig. 4, but showing a modified form of seal.

Referring more particularly to Figs. l to 4 of the drawings, the antenna will be seen to comprise a metallic shield or storage tube 1, which extends below the car body line and houses the antenna mast sections, when collapsed, shielding the mast against water, dirt and ignition noises. The car body line is indicated, in this instance, by the curved contour of the fender '2. The mast is of the conventional extensible type, consisting of two sections 3 and 4 of brass tubing, and one section 5, of stainless steel rod, each section collapsing within the next larger section, and the entire mast collapsing within the shield tube 1.

Surmounting the shield tube 1, and removably secured to the latter, as by means of a screw 6, is a body member 7, preferably made in the form of a Zinc die casting, which extends through an opening 8 in the fender 2. The body member 7 is secured to the fender 2 by means of spacers 9 and lll, and a steel nut 11, which is threadedly secured to the upper end o the body member and 2,850,305 Patented Sept. 2, 1958 bears against the top of the spacer 10, so as to firmly clamp all of the parts together. The spacers 9 and 1i) are also in the form of zinc die castings, the spacer having serrations 12 at its upper end (Fig. 3) which penetrate paint and undercoating and aid in establishing a good electrical ground connection to the car body. An insulator pad 13, of rubber, is interposed between the fender 2 and the lower edge of the spacer 10, and is provided with an opening 14 through which the body member 7 extends.

Disposed within the upper end of the body member 7 is a plastic bushing 15, and firmly staked within the lower portion of the body member is a second plastic bushing 16, these bushings serving not only to hold the antenna mast centered within the body member, but also to insulate the mast from the body member. Secured within the bushing 16 is a contact tube or finger 7 by means of which the signal from the mast is picked up and carried to the lead-in by means of the wire 18.

Threadedly secured to the body member 7, above the nut 11, is a cap nut 19 made of electrically insulating material, and having an inturned annular ange 2l). Secured to the flange 2l) is a grommet 21, which is made from a soft rubber-like compound, and is provided with an inwardly-extending llange 22 at its upper end, and an annular groove 23 into which the ange 2b of the cap nut extends to lock the grommet to the cap nut.

As indicated in Fig. 4, the flange 22 is of slightly less internal diameter than the external diameter of the mast section 3, so that it snugly engages the latter, so as to provide a watertight seal therebetween, .which permits easy movement of the mast section 3 with respect to the flange 22, yet prevents water from entering the joint between the flange and mast section and spoiling the good electrical characteristics of the antenna. Similarly, as shown in Fig. 4, the cross-sectional area of the flange 20 of the cap nut 19 is slightly greater than the crosssectional area of the groove 23 of the grommet 21, so that pressure is exerted on all three sides of the groove, resulting in a watertight seal between the cap nut and grommet. In practice, we have found that if the axial length of the flange 22 is about 1/8 inch, and it the ilange 22 is spaced at least 1A; inch from the groove 23, best results are achieved.

A seal is thus provided between the mast and the ground (body 7), consisting of the plastic cap nut and the grommet, which seal is not only elective to prevent entry of water into the joints between the seal and mast, but is also eiective to prevent accumulation of moisture on the mast section 3, since downward movement of the latter causes the grommet to Wipe such moisture from the mast section, thereby enabling the antenna to retain its good electrical characteristics in wet weather.

It may be further noted, at this point, that the pressure of the grommet on the mast and of the cap nut on the grommet is entirely independent of the tightness of the cap nut. ln other words, these pressures do not increase when the cap nut is tightened down on the body member 7, and hence, the cap nut cannot be tightened to such an extent that the mast becomes immovable with respect to the grommet.

The seal is inexpensive, and yet an effective one, comprising a minimum number of parts.

The invention also embodies an improved lead-in construction, which may be described with reference to Figs. l and 2 of the drawing. l

The body member 7 is provided With a laterally-extending tubular extension 24.

The lead-in is attached to the body member in a Watertight manner. It is of the conventional automotive type, consisting of an inner conductor of .010" Wire 1S en- Y casedl in polyethylene tubing 25, which, in turn, is covered with copper braid 26. The braid, in turn, is covered with a vinyl or polyethylene jacket27. The end of the lead-in which is connected to the radio set isrpro;n vided with a conventional end fitting 28. To the other end' of the lead-in is attached the novel water-tight fitting, which will now be described. A i ,Y

The litting consists oftwo sleeves, an inner sleeve 29, and an outer sleeve Si), between which are compressed the braid 26 and jacket` 27, the braid and jacket being compressed between the outer portions of the sleeves, and the braid 26 being compressed between the inner portions of the sleeves. By providing conical stepsldl and 32, on the inner and outer sleeves respectively, a Vjoint is formed which becomes tighter, the more pullV or tension is exerted between the braid andthe outer sleeve.

In assembling the fitting, thevinner sleeve 29 is inserted under the braid 26, andafter the inner sleeve has r been properly positioned, the outer sleeve 39 is drawn up over therbraid to the position shown in Fig. 2 after which the outer sleeve is secured, as by a press fit, in the tubular extension 24 of the body member.

Previously, end ttings have been applied to the leadin either by soldering or by compressing the braid only between two sleeves. vThe braid, in the latter case, was turned back over one of the sleeves. A water seal was obtained by stretching a rubber sleeve over the joint. The soldered joint was unsatisfactory because of theoccurrence of cold solder joints,fflux corrosion and poor appearance. in the other case, folding back the braid disturbed the interlacing of thepstrands and gave rise to weak joints. Y

The present construction of end fitting eliminates cold solder joints and flux corrosion, and does not disturb the interlace of the braid, so that a uniformly strong joint is obtained, as well as `an effective water seal, without the necessity of an eXtra Velement or part.

The end fitting, which has been described, may be used generally in connection with other types of antennas, such as the ed mast type antenna.

In Fig. 5, a modication of the invention is shown, in

which the flange 22 of the grornrnet 21' is of triangular cross-section, instead` of rectangular, so as to provide a somewhat more pliant or exible type of contact-of the ange with the mast section 3 than is provided by the ange 22. The diameter of the opening formed by the upper edge of the flange 22, in unstressed condition is of slightly less diameter than the outer diameter of the krnastvsectiou, so as to cause the` grommet to snugly embrace the mast section.

In this case, however, the seal between the cap nut 19 and the grommet is obtained primarily by screwing the cap nut down so as to compress the flange 33 of the grommet between the ange 20 of the cap nut and the plastic bushing 15. The inside diameter of the grommet, below the flange 22 is such that compression of the ange 33 will not cause this portion of the grommet to exert pressure on the mast section. Therefore, friction between the grommet and mast is not aected by the extent to which the cap nut is tightened, Since the flanges 29' and 33 provide a seal between the cap nut and grommet, the use'of thejgroove 23 in the grommet is not essential, and .the grommet need only be provided with a flange, such as the flange 33. Y

It is thus seen that we have provided a disappearing type automobile antenna which, in addition to the features and advantages which have been described, has excellent electrical and mechanical properties, as well as a highly pleasing appearance.

It is to be understood that the forms of our invention, herewith shown and described, are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of our invention, or the scope ofthe subjoined claim.

Having thus described our invention, we claim? n In an antenna of the character described, a body member, a cylindrical mast section movable axially through said body member, a grommet of non-metallic compressible material surmounting lsaid body member and having a bore of greater diameter than that of said mast section, saidl grommet having an internal unitary ange defining a diameterless thanthat of said mast section whereby to encircle and grip said mast section radially thereof, said grommet having an external circumferential recess, and Vmeans f or removably securing said grommet to said body member, said means consisting of anj element threadedly engaging said body member and having an internally-directed ange, of greater cross-sectional area than the crosssectional area of said recess,lengaged in said recess and adapted to compress said grommet axially thereof in response to said threaded engagement.

References Cited in the ile of this patenti UNITED STATES PATENTSV Irwin Oct. 19, 1937 Kosatka sept. 17,1957 

